1. Field of Invention
This invention relates generally to exercise apparatus such as a cross-country ski simulator machine or a stair climbing machine. In particular the invention relates to a restraint mechanism for exercise machines by which forces imparted to such a machine by a person are resisted. Still more particularly, the invention relates to a bi-directional restraint mechanism which offers a small restraint at zero or low velocity of a foot pad or step member for example, of an exercise machine, but presents a smooth acting increasing restraint with increasing velocity of said foot pad or step member.
2. Description of the Prior Art
Exercise equipment has used many forms of restraints or resistance to motion so as to enhance the muscle building and toning characteristics on a user of the machines. Weight stacks, springs, and the weight of the exerciser are commonly used to restrain motion of prior machines. Pneumatic or hydraulic damping mechanisms have been used to restrain motion of step members in stair climbing machines and others.
U.S. Pat. No. 4,023,795 illustrates a flywheel and friction brake to restrain foot pad motion of a cross-country ski simulator. Such simulator mounts flywheel on a shaft having rollers which are turned clockwise and counter clockwise on such shaft by skies coupled to the exerciser's foot pad. One way clutches on such rollers impart energy to such shaft in only one direction and only when the roller is energized by forward thrust of one ski at a speed greater than the speed of the shaft which is maintained in rotation by such flywheel. The result is that forward motion of a ski is not inhibited at zero velocity but is inhibited by the effect of the flywheel on the shaft (and of course the friction brake about the flywheel) only at velocities of the ski which match the angular rotation of the shaft and flywheel.
There has developed a need for a restraint device for exercise equipment that is inexpensive to build, which may be used with a variety of exercise machines, and which does not require the use of one way clutches.
3. Identification of Objects of the Invention
The primary object of this invention is to provide a smooth acting restraint device for use with exercise equipment which is characterized by low restraining force in response to low velocity of a foot pad of a ski simulator or a step member of a stair climber, for example, and by increasing restraining force in response to increasing velocity of such members, and is further characterized by equally restraining forces applied to it in opposite directions.
Another object of this invention is to provide a restraint mechanism for exercise equipment which restrains bi-directional motion without the need for one-way clutch mechanisms.